Series 477B Front View

Series 477B Handheld Digital Manometer

Representative image displayed of 475-0-FM|Actual product may vary


Series 477AV Handheld Digital Manometer

Measures Pressure, Flow and Velocity; ±0.5% Accuracy

The Series 477AV Handheld Digital Manometer is now available with pressure, flow, and velocity measurements along with a number of other convenient features. The built-in air velocity and flow calculations provide accuracy and conserve time and error associated with manual calculations. Also featured on this unit are adjustable zero and span values for calibrating in the field, as well as a damping feature to compensate for the fluctuating of readings.

NIST CALIBRATION available in Product Configurator.

Product Applications

  • Air flow monitoring, when used with a Dwyer® pitot tube
  • Duct static pressure
  • Commercial air balancing
  • Building-zone pressure
Starting at $232.95
Grouped product items
Model Description Availability* Qty Price
477AV-0 Digital manometer, range 0-10.00" w.c., air velocity/flow modes. 1-3 days*
477AV-00 Digital manometer, range 0-4.00" w.c., air velocity/flow modes. 2-3 Weeks*
477AV-000 Digital manometer, range 0-1.00" w.c., air velocity/flow modes. 2-3 Weeks*
477AV-1 Digital manometer, range 0-20.00" w.c., air velocity/flow modes. 1-3 days*
477AV-2 Digital manometer, range 0-40.00" w.c., air velocity/flow modes. 1-3 days*
477AV-3 Digital manometer, range 0-200.00" w.c., air velocity/flow modes. 2-3 Weeks*
477AV-4 Digital manometer, range 0-10.00 psi, air velocity/flow modes. 2-3 Weeks*
477AV-5 Digital manometer, range 0-20.00 psi, air velocity/flow modes. 2-3 Weeks*
477AV-6 Digital manometer, range 0-30.00 psi, air velocity/flow modes. 2-3 Weeks*
477AV-7 Digital manometer, range 0-100.00 psi, air velocity/flow modes. 2-3 Weeks*
477AV-8 Digital manometer, range 0-150.00 psi, air velocity/flow modes. 2-3 Weeks*


Air and compatible gases.
Wetted Materials:
Consult factory.
±0.5% FS, 60 to 78°F (15.6 to 25.6°C); ±1.5% FS from 32 to 60°F and 78 to 104°F (0 to 15.6°C and 25.6 to 40.0°C).
Pressure Hysteresis:
±0.1% of FS.
Pressure Limits:
See chart on catalog page.
Temperature Limits:
0 to 140°F (-17.8 to 60°C).
Compensated Temperature Limits:
32 to 104°F (0 to 40°C).
Storage Temperature Limits:
-4 to 176°F (-20 to 80°C).
0.42" (10.6 mm) 4 digit LCD.
See chart on catalog page.
Units of Pressure:
in w.c., ft. w.c., in Hg, psi, oz/in², mm w.c., cm w.c., mm Hg, mbar, Pa, kPa, hPa.
Units of Velocity:
fpm, fps, mph, m/h, m/s, k/h, knot.
Units of Flow:
cfm, m3/h, m3/s.
Power Requirements:
9 V Alkaline battery, installed non-functional, user replaceable.
10.2 oz (289 g).
Process Connections:
Two barbed connections for use with 1/8" (3.18 mm) or 3/16" (4.76 mm) ID tubing.
Two compression fittings for use with 1/8" (3.18 mm) ID x 1/4" (6.35 mm) OD tubing for 477AV-7 and 477AV-8 only.


  • Calculates and displays air velocity and volumetric air flow
  • Rugged aluminum case protects instrument from damage during transport/use
  • 9 selectable English and metric engineering units
  • Large, easy to read display with backlight for use in dark areas
  • Stores up to 40 readings with minimum, maximum and average statistics
  • Convenient all-in-one air velocity kit option available

Product Literature


Catalog Pages

Product Data Sheet


Model Chart

EXAMPLE 477AV 2 NIST 477AV-2-NIST, 477AV Differential Pressure Manometer w/ AV and Flow, 40” w.c./10 kPa Range, NIST Calibrated
RANGE   000
  1” w.c. / 0.249 kPa
4” w.c. / 0.995 kPa
10” w.c. / 2.49 kPa
20” w.c. / 5 kPa
40” w.c. / 10 kPa
200” w.c. / 50 kPa
10 psi / 70 kPa
20 psi / 140 kPa
30 psi / 200 kPa
100 psi / 700 kPa
150 psi / 1000 kPa
Certificate of Calibration
Factory Calibration Certificate
NIST Traceable Calibration Certificate


We use series 477AV digital manometer. What is the recommended calibration interval?
We do not have an official recommended calibration interval. However, we would suggest checking the calibration at least once or twice a year depending on the application and how often the unit is used.
Is there a manometer that is compatible with chlorine gas and sodium hydroxide (bleach)?
Unfortunately, we do not have any manometers available that can handle chlorine gas or sodium hydroxide (bleach).
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Model Description Availability* Price
166T Telescoping pitot tube 2-3 Weeks*
A-201 Rubber latex tubing has less tendency to kink in storage and occupies less space, thus is best for portable work. 3/16" ID, 9' length. 1-3 days*
A-303 Portable static pressure tip, for 3/16" ID rubber or plastic tubing with 4" insertion. 1-3 days*
A-375 Compression fitting connections, 1/8" tube to 1/8" NPT male 1-3 days*
A-397 Rugged step drill, quickly provides true round holes in thin materials, no center punch needed to start, automatically de-burrs drilled hole, high speed steel, drills 3/16" through 1/2" holes in 1/16" increments. 1-3 days*
A-402A Carrying case for most manometers; tough, gray nylon pouch, double zippered with belt loop 1-3 days*
A-463 Plastic carrying case with foam liner for 475-1-AV air velocity kit - 13-1/2" x 10" x 2-3/8". 1-2 Weeks*
A-472T 475-T AV telescoping pitot tube air velocity kit less manometer Less Than 1 Week*
A-47X-BOOT Rubber boot for manometers (manometer not included) 1-3 days*